Oil well drilling transmission



March l1, 1952 c. M. Q'LEARY OIL WELL DRILLING TRANSMISSIN 3Sheets-Sheet l Filed May 8, 1947 ,fllllllnv fwn'.

Vrh

March 11, 1952 c. M. OLEARY oL WELL DRILLING TRANSMISSION 5 Sheets-Sheet2 Filed May 8, 1947 ....UIIIIIIIII lllllllllll L ma N6 VK @a M mM w 5March 1L, 1952 c. M. O'LEARY 2,588,403

@1L-WELL DRILLING TRANSMISSION Filed May 8, 1947 5 Sheets-Sheet 3MLQS'aQW/m Patented Mar.l 11, 1952 UNITED STATES PATENT OFFICE 2,588,408y on. WELL DRILLING TRANSMISSION Charles M. OLeary, Los Angeles, Calif.Application May s, 1947, serial No. 746,664

(c1. ass- 19) 13 Claims.

The present invention relates to a well drilling machine, andconstitutes an improvement over apparatus for the same purpose disclosed1n applicants copending applications, Serial No.

676,450, filed June 13, 1946, and Serial No. 647,677, filed February 15,1946.

It is the general object of the present invention to provide a rotarywell drilling machine characterized-by its extreme fiexibility, highefciency and ease of control.

` Another object of the invention is to provide, in an` apparatus of thetype mentioned, an 1mproved form of change-speed transmission mechanismcapable of driving either the hoisting drum or the rotary table at aplurality of different forward speed ratios as well as at one or morereverse speed ratios, and in which these results are achieved with aminimum number of parts.

Another object of the invention is to provide apparatus of the typementioned incorporating means for automatically controlling the pressureof the rotary drilling bit on the bottom of a hole during drillingoperations; and, more particularly, to reduce the drill bit pressure inaccordance with increases in the torque required to rotate the drillstem but at a smaller percentage magnitude of change.

Another object of the present invention 1s to provide `improved andsimplified means for adjusting the sensitivity of the drill stem weightcontrol mechanism.

Other objects and advantages of the invention will become apparent fromthe following specification', 'the accompanying drawings and theappended claims.

' In the drawings:

1 Figure 1 is a general plan view of the complete apparatus, certainparts being shown more or' less diagrammatically;

o Figure 2 is a longitudinal section through the change-speedtransmission mechanism shown in Figure 1;

Figure 3 is a transverse section taken on the line 3-3 of Figure 2;

, -Figure 4 is a fragmentary section taken on the line 4 4 of Figure 2;

. Figure 5 is a fragmentary section line 5--5 of Figure 2; and i 1 V-Figure 6 is a -fragmentary section taken on the line 6--6 of Figure 2. fAs best shown in Figure 1, the apparatus includes a rotary table I,which may be of conventional construction and which is adapted to rotatethe drill stem during the drilling operation in the usual manner, and lahoisting drum 2, upon taken on the which is Wound the 'cable which,through suitable block and tackle, not shown, supports the major portionof the weight of the drill stem during the drilling *'operation, theunsupported portion of the weight of the drill stem being relied upon todevelop the necessary pressure between the rotary drill bit and thebottom of the hole. The hoisting drum 2 is also utilized to hoist thedrill stem from the well when it is necessary to replace or sharpendrill bits, etc.

The drum 2 is provided in the usual manner with brake flanges 3 and 4adapted to co-operate with brake bands, not shown. The drum 2 ispreferably freely journaled on a stationary shaft 5, which also journalsa multiple sprocket 6 adapted to be connected to the drum by operationof an air-operated clutch I positioned largely within the brake flange3. Air for operating the clutch 'I is supplied from a pipe 8 through anopening passing axially through the shaft 5 in the usual manner. Thedetailed construction of the rotary table, hoisting drum and pneumaticclutch 1 forms no part of the present invention and may be of anydesired form. The rotary table l is driven from a countershaft 9 by apair of sprockets I0 and II connected by a chain I2.

The apparatus is driven by two or more engines or motors, preferably ofthe internal combustion type, in the nianner shown in greater detail inapplicants copending application, Serial No. 676,450, filed June 13,1946. However, in Figure 1 only one of the driving engines is shown.Thus, as illustrated in Figure 1, an internal combustion engine I3 hasits power output shaft I4 connected to the input of a hydrokinetictorque converter I5. The hydrokinetic torque converter may be of anydesired or conventional construction, but is preferably of the typedisclosed in greater detail in applicants copending application, SerialNo. 740,673, filed April 10, 1947, now Patent No. 2,558,976 issued July3, 1951, to which reference may be had for further details ofconstruction. It is sufficient to note here simply that the torqueconverter I5 automatically transmits torque at an infinitely variabletorque ratio from the input shaft I4 to the output shaft I6, this ratiobeing maximum when the difference between the speeds of the shafts I4and I6 is greatest and progres;

sively diminishing as the speeds of the shafts approach each other. Thetorque converter also incorporates a liquid circulating system includinga radiator II, input and output conduits I8 and a differentiallyoperated radiator fan I9, in order to prevent development of excessiveheat within the converter. all as set forth in. greater andhydrok'inetic torque converter power: sources identical in constructionto that previously de"- scribed.

The apparatus includes a power input counter#-v shaft 24 on which isfreely journaled a sleeve. 25 which carries a sprocket 26 and a doublesprocket 21. The sleeve may be fixed to the shaft 24. by operation ofthe pneumatically operated clutch 28, which is engaged upon applicationof air under pressure to a conduit 29 and an associated opening (notshown) passing through the shaft 24, in accordance with conventionalpractice. The double sprocket 22 is permanently connected to thecountershaft 24 by a chain 30 and a sprocket 3| fixedto the shaft 24. Asthe result of this construction, the engine or engines associated withthe chain 23 are at all times connected to the shaft 24, while theengine I3 is at all times connected to the sleeve 25". The shaft 24 andsleeve 25 may be driven independently by the separate power sources; or,upon engagement of clutch 28, may be connected together and the powerfrom two or more power sources supplied to both the shaft and thesleeve.

The apparatus includes a main change-speed transmission, indicatedgenerally at 32. The' transmission 32, as best shown in Figure 2,`includes a casing 33 in which is journaled a main shaft 34 .whichprojects from thev housing at both ends. A sprocket 35 is fixed on theshaft 34 near its right-hand end, and` a sleeve. 36 is freely journaledon the right-handl end of shaft 34 and carries a sprocket 31. Sprocket35 is connected by means of a chain 38 to a sprocket 39, which is freelyjournaled on a shaft 40.

Sprocket 39 may be connected to shaft 40 by l.

means of a dog clutch 4| in order to drive a. pair of cat heads 42carried by the shaft. The sprocket 31 and its sleeve 36 may be fixed tothe shaft 34 by means of an air-operatedclutch 43.- Sprocket 31 isconnected byy means of a chain 44.to a sprocket 45 fixed on thepreviously mentioned countershaft 9, and` thus serves to drive therotary table. I. The left-hand end' of the shaft 34 hasfreely journaledthereon a, sleeve 46 on which are mounted a multiple. sprocket 41,y asecond multiple sprocket 48 and a. single sprocket 49. All three ofthese sprockets, 41, 48 and 49 being fixed to sleeve 46, rotatetogether. An air-operated clutch 50 will, on actuation, connect thesleeve 46 to the shaft 34. The multiple' sprocket 41 is connected bymeans of chains 5| to a multiple sprocket 52 carried by a sleeve 53which is freely journaled` on the: shaft24. An air-operated clutch54'wil1, on actuation, con-- nect the sleeve 53 tothe power inputcounter shaft 24. The multiple sprocket 48 is connectedv by chains 55 tothe multiple sprocket 6 of. the hoisting drum 2. The single sprocket 49is conf' nected by means of ar chain 56 to a sprocket 51 carried by asleeve which is freely journaled on a countershaft 59. Thesleeve and itssprocket 51 may be connected to the shaft 59 by engage-- ment of anair-operated clutch 58. The shaft -59 is journaled withinA the casing 33and pro-- jects at both ends therefrom.

tubular power input shaft 69 which surrounds the shaft 34 and projectsfrom the right-hand end of the transmission housing, as viewed in Figure2. The tubular shaft 69 has fixed thereto a multiple sprocket 6|, whichis connected by means of chains 62 to the multiple sprocket 21 on thesleeve 25.

The transmission 32 includes a pair of substantially identical planetarytransmission units, indicated' generally at' 63'J and 64", which unitsare connected in series between the shaft and the shaft 34. Thetransmission unit 63 includes aplanet cage member 65, which is fixed toa web 66 secured to the inner end of the tubular shaft 60. The planetcage 65 includes a pair of annular side plates 61, which plates aresecuredto the web 66 by means of a plurality of webs 68 which lie inradial planes about the axis of shaft 34, extend between the side plates61, and connect the latter to the web 66. The webs 68 arecircumferentially spaced, and between each adjacent' pair of webs ismounted aY planet gear cluster 69 the gear clusters 69 being journaledupon shafts 10 which are fixed at their ends in the side plates 61 bymeans of pins 1I. The

planet cage 65 also includes a cylindrical portion 12 whichr surroundsthe outer edges of the webs 68 and extends from the leftehand sideplatein Figure 2 inwardly over the smaller of the `two gears on eachofthe gear' clusters' 69;

The larger of the two gears'on each of'thegear clusters 69 meshes witha. ring gear 13 which is supported by a cylindrical housing member 14.Any desired form of connection mayfbeemployed between the ring gear 13and the-housing 14; However, inv theA preferred construction show-n inthe drawings, and particularly in Figure 4, the ring gear 13 is providedwith external teethl which a're adapted to t matingV teeth on the;interior of the housing 14. Limited play is provided between the teethon the ring gear'and the-heus; ingV in order to permit self-alignment ofthe ring gear. Thel ring gear is held against displacement from thehousing by means of a retaining ring 15.

The housing 14 is provided with an inwardly directed end' flange 16which is journale'd by means of bearings 11 on the tubular shaft- 60. Inthis'connection, it will be notedv that' the tubular shaft 60' issupported on the housing 3'3` by meansv of' bearings 18 and the shaft34`is. jour-inaled within the tubular shaft 60by means of bearings 19.

TheA smallerl ofr4 the two gears in each gear cluster 69`meshes with asun gear 80 which is xed to the right-hand end of a tubular shaft 8 I?.A bearing 82 is provided between the web- 66 of the' planet cage 65 anda right-hand extension of the tubular shaft 8|. Bearings 83' are "alsoprovided between the tubular shaft 8| and the` main shaft 34. Thetubular shaft 8|l isA journaled by'means of bearings 84 onv atransversel Wall 85 formed within the casing.

Means are provided for selectively holding the housing 14 againstrotation or` vconnecting' the housing to the planetcage in orderv toobtain two different speed ratios ln the drive connection between theshafts 60 and 8|. Thus, aslbestshown in Figure 3, the housing 33 isprovided with three circumferentially spaced openings 86, and identicalbrake mechanisms are associated with each. suchopening. Thus, as shownati the top of Figure 3, the opening 86 is closed by a-cover plate 81having a flat inner surface. A pair of one- Way brake blocks 88 and 89is-po'sitioned within the. openings and is` adapted to' wedge betweenthe inner surface of the cover plate 81 and the periphery of thecylindrical housing 14. Coil springs 90 normally urge the brake blocks88 and 89 in wedging direction, but the brake block 88 is normally heldout of wedging position by means of. a dog 9| carried by a piston rod 92which is fixed to a piston 93v slidable within a cylinder 94 formedintegrally with the cover plate 81. The right-hand end of cylinder 94,as viewed in Figure 3, is closed by means of a plug 95 having an airsupply pipe 96 associated therewith. A spring 91 normally acts on thepiston'93 to hold the parts in the position illustrated in Figure 3, inwhich position the dog 9| holds thebrake block 88 in inoperativeposition. With the parts in` the position shown in Figure 3, the housing14 is free to rotate in a counterclockwise direction, but it cannotrotate in a clockwise direction due to the fact that on such rotationthe brake block 89 will automatically wedge itself between the peripheryof the' housing and .the inner surface of the closure plate 81. If airunder pressure is supplied to pipe 96, the piston 93 will shift to theleft, compressing spring 91 and thereby releasing the dog 9| from thebrake 'block 88 and engaging it with the brake block 89. Under thesecircumstances, counterclockwise rotation of the housing 14 is preventedby the automatic wedging of the block 88 between the periphery of thehousing 14 and the inner surface of the plate 81, but the housing isthen free to rotate in a clockwise direction due to the fact that thedog 9| preventsv wedging action of the block 89. Three identical sets ofbrakeblocks and asso ciated operating mechanism are associated with thehousing 14, as shown in Figure 3. Consequently, the braking forces arebalanced and impose no radial loads on the elements of the transmission.As will be apparent, all three of the 4air supply pipes 96 associatedwith these brake block mechanisms will be connected to a common controlvalve, with the result that they are in all cases simultaneouslyoperated.`

The housing 14 may be connected to the planet cage 65 in order toestablish a 1 to 1 or direct drive ratio through the transmission 63.This is accomplished by means of a cone clutch element 98 which has ahelical spline connection with the cylindrical portion 12 of the planetcage and which has a cone clutch surface adapted to engage a mating coneclutch surface formed on the left-hand edge of the cylindrical housing14.

As best shown in Figure 5,1 the helical splines 99 Aformed on 'the coneclutch element 98 and the mating spline teeth |00 formed on the planetcage 65 extend at such an angle that the forces imposed upon the coneclutch element 98 by the clutch face on housing 14 and the teeth |00 onplanet cage 65 when the clutch is engaged, housing 14 held stationary,and power is supplied to the transmission by shaft 60 tend to effectdisengagement of the clutch element 98. This facilitates clutch release.Theclutch 98 is engaged by means of an annular piston |9I, which isaxially slidable within an annular cylinder formed by a pair of annularmembers |02 and |03 secured to the transverse wall 85 of thetransmission. Air under pressure may be supplied tothe interior of theannular cylinder through an air inlet pipe |04 to effect movement of thepiston |0| to the'right, as viewed in Figure 2, and, consequently,engagement of the clutch element 98 with the mating clutch surface onthe `housing 14. A ball thrust bearing |85 is providedbetween theannular piston Isl' and the inwardly directed web on the clutch element98, to eliminate friction and prevent rotation of the annular piston|0I. Coil. springs |06 are positioned between the inwardly directed endiiange or web of the clutch element 98 and the left-hand annular ring 61of the planet cage, and thus act to urge the clutch element 98 out ofengagement with the housing 14 at all times. The springs |06 are helicalsprings and are positioned in suitable pockets, not shown, formed in theannular ring 61 intermediate the planet shafts 10.

As the result of the above construction, if power is supplied to shaft60 and air is supplied to pipes 96, the ring gear housing 14 will beheld stationary due to the fact that shaft 60 rotates in the directionindicated by the arrow in Figure l and hence tends to rotate the ringgear in a counterclockwise direction, as viewed in vFigure 3. The clutchblocks 88, under these circumstances, prevent such counterclockwiserotation, and, as a result, the planetary transmission unit 63 providesa speed increasing or overdrive speed ratio connection between thetubular shafts 60 and 8|. It is preferred that the relative sizes of thegears employed in the transmission be so chosen that under thesecircumstances shaft 8| be rotated at twice the ,speed of shaft 60. rlhedirection of rotation will be the same. When the air under pressure isdis. connected from pipes 96 and connected to pipe |04, the clutch 98will engage and lock the transmission unit 63 in its direct drive or 1to 1 ratio, thus xedly connecting shafts 60 and 8|.

Thep'lanetary transmission unit 64 is identical in construction and modeof operation to the transmission unit 63, previously described, exceptthat the one-way brake blocks which correspond to the brake blocks 89 oftransmission 63 are omitted and the sun gear |01 is fixed to the shaft34. Therefore, the transmissionunit 64 will either establish a 2 to 1overdrive connection or a direct drive connection between the tubularshaft 8| and the -shaft 34, depending uponwhether or not air is suppliedto the brake blockA operating mechanism associated with the ring gearhousing |08 of the transmission unit 64 or to the pipe |09 whichsupplies air to the annular piston ||0 for the cone clutch element Sincethe transmission unit 64 is otherwise similar to the transmission unit63, previously described, further description and illustration arebelieved unnecessary. However,A hereinafter the one-way brake blocks fortransmission 64, which correspond to the brake blocks 88 associated withthe transmission unit 63, and the air supply pipes for transmission 64,which correspond to pipes 96 of transmission 63, will be re ferred to bythe numerals 88a and 96a, respecd tively. The left-hand end of the mainshaft 34 is journaled by means of bearings I2 in the lefthand end of thehousing 33. A bearing ||3 is provided between the shaft 34 and theplanet cage ||4 of transmission 64, and a bearing H5 is provided betweenthe ring gearhousing |08 and the tubular shaft 8|.

In addition to the above, the planetary trans mission unit 64 differsfrom the unit 63 in that the ringgear housing |08 of the transmissionunit 64 has secured thereto a gear |l|6 which meshes -witha gear ||1fixed to the previously mentioned countershaft 59.

The right-hand extremity of the shaft 59 projects from the housing 33vand Vhas'freel-y jour.- naled thereto a sprocket. H8, which may. beclutched to the shaft by means of a' manually` operable dogV clutch H9.The sprocket H8 connected to the power input countershaft 24` through aninfinitely variable positiv-e displacementf'ihydraulio transmission,indicated generally at |20, one sprocket, |-2|, of thetransmission`being connected to the sproclfiet` H8 byl a chain"|22, andthe other sprocket, |23., vof they transmission being connected by achain |24 to a sprocket |25 freely journaled .on the shaft 24. Amanually-operable dog clutch |26 is adapted to connect the sprocket |25to the shaft 24.

While any suitable form of change-speed positive drive transmission maybe employed as the transmission |20, the preferred form is a positivehydraulic transmission of Athe wobble plate typeQf more or lessdiagrammatically illustratecl inthe drawings, transmissions of this typeinclude a hydraulic pump |28'which is connected toa hydraulic motor |21by means of piping |29 and |30. Either the pump or the motor'may be ofthe fixed positive displacement type, but the othergmust be a variabledisplacement rnit. In the preferred form of the mechanism, the motor isa fixed displacement hydraulic motor and the pump |28 is a variablepositive displacement pump vof the wobble plate type, wherein the strokeof the pistons is a function of the angularity. of an adjustably mountedwobble plate and means are provided to fix the wobble plateA at anydesired angle. Thus, as shown fragmentarily in Figure-6, thepvrnpelement |28 is provided with a wobble plate member. illustratedfragmentarily at |3|. The wobble plate is provided with an upstandingstud |32 on which is fitted a spherical element |33 havingy acylindrical boreto receive the stud. The element |33, in turn, is fittedwithin a spherical socket ina reciprocating plunger |34 which is fittedwithin a guide member |35 secured to the top of the pump element |28.The position of the plunger |34 may be adjusted by hand wheel |36 whichis secured on a threaded shaft |31, the threads of which t a threadedopening in the guide |35. The threaded shaft is connected by means of .a

reduced extension |38 to the plunger in any desired` manner which willpermit rotation of the extension independently of the plunger. Thus, asshown, the extension is provided with a head |39 which is secured bymeans of an internally threaded ferrule |40 to a threaded projection cnthe -A-plunger. As a result of this construction, the angularity of thewobble plate |32 may be adjusted by rotation of the hand wheel |36, andthatangularity will remain fixed so long as the position of the handwheel is unchanged. Thus, by increasing the angularity of the wobbleplate, the displacement of the pump |21 for each revolution of the inputsprocket |2| will be increased and the torque multiplication through thehydraulic transmission |20 decreased, and vice lversa.

As will be pointed out hereinafter, the innitely variable transmission|20 is employed `when the apparatus of the present invention is-utilized to control the pressure ofthe drill bit on the bottom of thehole during drilling operations to transmit to the hoisting drum atorque which is a function of the torque required to rotate the table i.This is achieved by driving the table from tubular shaft through theplanetary transmission units 63 and 64 to shaft 34 and thence to thetable and simultaneously absorbing l:the .reaction torque imposed uponthe ring gear housing |08 of transmission 64 byconnecting it .to `thehoisting drum vthrough the-transmission |20. vAt. the same time, alarger portion of the weight of thedrill `stem is supported :by aseparate engine from that utilized to drive the table. YThe infinitelyvariable transmission |20 is utilized in place of aV direct gearconnection solely for the purpose of permitting an adjust-.- ment of thesensitivity of the `drilling control. It is desirable, therefore, toutilize as small an infinitely varia-ble transmission as possible inor.- der to reduce cost, size and weight. This objective is realized inaccordance with the present in vention by making the gear H1substantially smaller than the gear H6 and by making the sprocket |2|substantially smaller than the sprocket H3. This greatly reduces thetorque imposed on the sprocket |2| of the hydraulic transmission |20. Inaddition, the sprocket Y|23 of the transmission |20 is connected to theinput countershaft 24, which is a relatively low torque shaft. The driveconnection between the shaft 24 and the drum through chains 5| and 55greatly reduces vthe torque supplied to the shaft 24 by the drum 2.vSince during drilling operations the speed of rotation of the drum isvery low, this decrease in the torque transmitted through thetransmission |20 will not result in an objectionable .increase in speedof the transmission |20, and, therefore, the use of a small transmissionunit is possible.

Any suitable or conventional means may be provided for controlling thesupply of air to the clutches and the pipes 96, 93a, V|534 and |99. Itis preferred, however, that each of these clutches and control elementsbe supplied with air through an independent three-way Valve, each valvebeing independently operable to connect the clutch or other controlelement either to a source of air under superatmospheric pressure or tothe atmosphere. Solenoid operated valves are preferred for `thispurpose, since they may be'controlled remotely from the drillersstation. Since such control systems are well known and may be of anyconventional or desired arrangement, further illustration or descriptionis Vbelieved unnecessary. However, one suitable type of control systemis disclosed in applicants copending application, Serial No` 647,677,filed February 15, 1946.

While the speed ratios of the various drive connections through theapparatus may be `Varied widely, as desired, to meet any givenconditions, the operation and advantages of the invention may best beillustrated by selecting a speciiicembodiment of the invention. Thus,for purposes of the subsequent description of the operation of theapparatus, it will be assumed that the-speed ratios of the various driveconnections of the apparatus are as follows:

The ratios of the drive connections between the various converter outputshafts, such as the converter output shaft IS or the correspondingconverter output shaft (not shown) associatedwith chain 23 and the powerinput countershaft 24, are vall 1 to 1 or direct drive ratios. Thedriveconnection provided bychain 62 between sprocket 2l and sprocket 6|onshaft 5,0 is 2 to l, i. e. sprocket 21 rotates at twice the speed ofsprocket 3 I. As previously indicated,l the planetary transmissions 33and 04 will each provideeither a direct drive or 1 to 1 ratio from theplanet cage to the vsun gear or a 1 to 2 drive ratio from the planetcage to thesun gear. The drive connection from thelgear I3 -to the gearlisa 1 tvo-2 drive ratio. The .ratio between the sprocket H8 and thesprocket |,2| is `a 1 to 4 ratio. "I g-heratlo .betweenthe Sprocket |23andthe sprocket |25 `gear units 63 and 64 is immaterial.

of the transmission 32. vdriven solely from `the engine I3 or, byengage- L, vment of the clutch 28, from the additional enginesassociated with the chain 23. For second .G and the tubular is a 1 to 1ratio. The drive between the sprocket 52 and the sprocket 41 is a 4 to 1ratio. The .drive between the sprocket 48 and the drum `sprocket 6 is a3 to 1 ratio. The drives between the shaft 34 and both the cat headcountershaft and the table sprocket I0 are l to 1 drive ratios. Thedrive ratio between the sprocket 51 and the sprocket 49 is a 2 to 1ratio.

The operation of the apparatus under the varying conditions encounteredin deep rotary' well drilling is as follows:

Hoistig operations Low gear drive is obtained by engaging clutches 1 and54, thus establishing a drive connection bev. tween the power inputcountershaft 24 and the drum independently of the transmission 32. Atthis time. the clutches 43, 50, 58, IIS and |26 are disengaged-and thecondition of the planetary This proq vides a torque multiplication of 12to 1 between the shaft 24 and the drum, and the engine torque ismultiplied by the hydrokinetic torque converter I5 before it istransmitted to the shaft 24, thus -providing a further increase in thetorque dethe Shaft 2 4.

Second, third and fourth speed ratio drives to the drum are providedthrough the trans- .mission 32. Thus, to establish the second speed 35ratio, clutch 50 is engaged and clutch 54 disengaged. The drive is thenfrom the sprockets 21 to the sprockets 6| on the tubular input shaft 60The sprockets 21 may be speed, both of the planetary transmission units63 and 64 are placed in their 1 to 1 or direct drive I ratios byengaging the clutch elements 98 and 4 -between the sprockets 21 and 6|is a 2 to, 1 ratio and the drive between the sprockets 48 and 6 is a 3to 1 ratio, this establishes a torque multiplica- 10 sure to the pipes96a which render effective the one-Way clutch blocks 88a associated withring gear housing |08 of transmission unit A64. This establishes a 1 to2 overdrive connection between the shaft 8| and the shaft 34, therebyproviding a 11/2 to 1 torque multiplication between 4the sprockets 41and the drum. The remaining clutches and control elements will remain inthe condition described in connection with third gear. It will be notedthat by providing a low gear drive independent of the transmission 32and by providing substantial torque multiplication between the output oftransmission 32 :and the hoisting drum, the transmission 32 is relievedof .i the heaviest loads and hence may be relatively small in size andlight in weight.

To drive the drum in reverse, clutches 43, 50, 54, II9 and I 26 aredisengaged and clutches 1 and 58 engaged. Under these circumstances, thedrive to the drum is from sprockets 21 to the input shaft 60 of thetransmission 32 through the transmission unit 63, which may be either inits high or low gear ratio, to the transmission unit 64, which must thenbe in its direct or 1 to 1 ratio, and thence to the countershaft 59through gears I|6 and I I 1. From the countershaft, the drive is throughsprocket 51, chain 56 and sprocket 49 to the sleeve which4 carries thesprockets 48 and thence to the drum sprockets 6. It will be noted thatsince the drive from the ring gear |08- of transmission 64 to the shaft59 is a direct `gear drive while the return drive from the shaft 59 tothe sleeve 46 is a chain drive, the direction of rotation of the sleeve46 will be reversed with respect to that of the housing |08 and thetubular input shaft 60. This, therefore, drives the drum 2 in reverse.As previously indicated, for this purpose the transmission unit 64 islocked in its 1 to 1 ratio by supplying air under pressure to 0 pipe |09and thus engaging the lcone clutch eletion of 6 to l between thesprockets 2'1r and the455 drum. i

Third speed is obtained by disconnecting line |04 from the source of airunder pressure and supplying air `under pressure to the pipes 536.`4This disengages the cone clutch 98 of transmis- 6 sion unit E3 andpermits the one-way brake blocks 88 to engage the ring gear housing 14and Yhold it against rotation, thus establishing a 1 to 2 overdriveconnection 4between the tubularshaft shaft 8|. clutches and controlsremain in the condition previously described for second gear. with theresult that the tubular shaft 8| is directly connected throughtransmission unit 64 to the shaft The remaining y34 and thence to thesprockets 48. This estab- 70 lishes a 3 to 1 torque multiplicationbetween the sprockets 21 and the drum. y

V Fourth or high speed is similarly obtained by disconnecting pipes |09from the source of air under pressure and connecting air under pres- 7ment III. This establishes a positive drive connection between thetubular shaft 8| and the ring gear housing |08. If during reverseoperation of the drum the transmission unitl 63 is in itsv low gear ordirect drive ratio, the torque multiplication between sprockets 21 andthe drum will be 6 to 1. This condition is established by supplying airunder pressure to the pipe |04 and thus engaging the cone clutch 9 8. Toobtain a lower dtorque multiplication, transmission unit 63 is placed inits overdrive conditionv by disconnecting air under pressurefrom pipe|04 and connecting air under pressure to pipes 96. This provides atorque multiplication of 3 to 1 between the sprockets 21 and the drum inreverse. y

Whilethe control valves which control the various drive connectionsthrough lthe transmission may be operated manually in any desiredmanner, it is preferred for heavy duty hoisting op- 0 erations tocontrol the speed ratios of the drive connections to the drumautomatically in response to the speed ratio of the hydrokinetic torqueconverter I5 or the similar converters asscciated withthe additionalengines (not shown) in order to maintain the speed ratio of theconverter or converters Within their range of maximum eiciency. Suitablemeans for this purpose are disclosed in applicants above mentioned oopending application, Serial No. 641,677, filed February 15, 1946. Thisautomatic control mechanism may be arranged to control all four of thehoisting drum speed ratios, but for most practical purposes it will besufficient to controlv autol64 in reverse. .cage |4 in reverse, but suchreverserotation is ,prevented by the one-way clutch blocks 89 ofVsprocket I9. -tubularshaft 69 of the transmission is held stationary,it is Anecessary to disconnect engine I3 .from shaft I3 in any desiredmanner, as, for exlamplefby draining the liquid from the convertershown) .assegna During .such operations as lowering the drill stem,theenginesand hydrokinetic torque kconverters may be utilized vas '.abraketo support or stop itheflowering movement of the drillstein as Thetransmission though preferably ata relatively high speed ratio in orderYto `reduce the speed of the outputshaft of the converter. The brakingtorque applied to .the drum is lthen vcontrolled by adjustment of 4theengine throttles, and the heat generated in the converters is dissipatedby the converter. liquid cooling system.

M anualY drilling operations Ii desired, the apparatus may .be utilizedin the performance of ordinary drilling operations, .in

l torque converter and the table.

The .lowest speed ratio is achieved by engaging clutches l54, 58 and thecone clutch element 98 of transmission unit 63. .pipes |09 or96. Underthese circumstances, Athe .power is delivered fromshaft 24 through chain5| No air is supplied to the to the sleeve 4.5 and thence through chain56 and `:clutch 5B to thercountershaftfiiil. The countershaft, through.gears |.I'I and H6, then rotates the ring ygearhousing I 08 of thetransmission unit This tends to rotate the planet `.the planet cage oftransmission unit 64 remains fstationary and the sun gear |07 rotatesforwardly, i. e. in an opposite direction vto the direction of rotationof the ring gear housing |08. This drives shaft 34 and, consequently,the rotary table in a forward direction at a torque multiplication ,of'8to 1 between the shaft 24 and the table drive Since under theseconditions the I5. The power to drive the tableis thus supplied throughchain .23 from another engine (not The inconvenience of disconnectingfengine VI3 in order to establish the above low drive `ratios is of minorimportance due to the fact that such a high degree of torquemultiplication is seldom, il ever, required in ordinary operations.

Second speed is obtained by driving from the v.power input countershaft24 through chain 5I and clutch V5|) directly to the transmission shafty34. This will provide a 4 to 1 toroue multiplica Aby engine I3,clutch28 must Ibe engaged. in which event shaft 69 will idle forwardlywithout any connection to the shaft 34 since the clutch elernents 98 andI will be disengaged and the ring gear housings 14 and |08 will idleforwardly.

Third-speed is established by driving from engine I3 through theconverter l5 to sleeve 25 and thence to the Vtransmission inputshaftl'with both ofthe planetary transmission units 33 and 34 in theirlow gear or direct drive ratios. This will drive the shaft 34 andprovidea2 to 1 torque multiplication to the table drive sprocket Ilifrom thesleeve 25. Under these circumstances, clutches 50, 54, 58, IIS and |26are disengaged.

' If only one engine is required to drive the table,

which is usual, clutch 28 will also be disengaged and both 'of the coneclutch elements 98 and III of the transmissions 63 and 64 will beengaged by application of air under pressure to the pipes |04 and |09.No air will be supplied to the pipes 96 and 96a.

Fourth speed is established in the'same manner as third speed exceptthat cone clutch element 98 of transmission unit 63 is disengaged andair runder pressure supplied to pipes 96, lthus placing transmissionunit 63 in its 1 to2 overdrive ratio. This provides a'torquemultiplication betweenthe sleeve 25 and the table drive sprocket I0 of1"to `1.

Fifth speed is achieved in the same manner as fourth speed except thatthe cone clutch element III of transmission unit B4 is disengaged andair vunder pressure is supplied to pipes 96a of transmission unit B4,thus placing that unit in its 1 to2 overdrive ratio. This provides a 1to`2 overdrive connection between the sleeve 25'and the table drivesprocket IIJ.

Higher speed ratio drives for thetable will not ordinarily be required.However, it is lpossible to obtain a still higher speed'drive vfor thetable by driving from the sleeve 25 into the input shaft 69 of thetransmission and from shaft 24 through sleeves 53 and 46tothecountershaft59. IThis is accomplished by engaging clutches 54, 58'andthe cone clutch element 98 'of transmission unit 63. As a result.the planet cage |I4 `of transmission unit 64 will rotate "forwardlywhile 'thering vgear housing |08 of transmission unit 54 will rotatereversely, thereby driving the 'sun gear |91 vforward at a highoverdrive speed ratio. Clutch 28 may be engaged. but in that event theengines normally associated with chain 23 should be `disconnected unlessit is desired to 'drive ythe table with more than one engine.

A still higher speed ratio can also be obtained, if desired. by placingthe transmission unit 53 Yin its overdrive ratio under the abovecircumstances.

Automatic drilling When it is desired vtoutilize 'the 'apparatus toautomatically control the pressure 'o'f the drill bit on `the bottom ofthe hole, kclutches 'I and 54 are engaged 'and clutch 50 disengaged. The'engine and torque converter (not shown) associated with the chain 23are then so set by adiustment of the engine throttle that they willsupply,

through shaft 24 and chains 5| and 55, asuiiicierit torque to thehoisting drum to 'support a desired proportion of the weight of thedrill stem. This proportion of the weight so supported will remainconstant for any given setting of the throttle of the enginedue to thefact that the speed ofthe drum during drilling, and, therefore, thespeed of the output shaft of the vtorque converter, is negligiblecompared with the engine speed. yUnder these circumstances, the torquedelivered by the torque converter to the drum through the abovedescribed connections will, for all practical purposes. be totallyunaffected bythe minor variations in drum speed normally encountered.

The drill stem supporting toroue supplied in 4the above describedmanner, which remains at a `constant value forany ygiven throttle.settingis then augmented by supplying to the drum an additional torquewhich varies in accordance with variations in the torque required torotate the drill stem. This is accomplished .by driving the table fromengine I3 through sleeve 25, chain 62 and transmission 32 to the shaft34. The reaction torque thus imposed on the ring gear of transmissionunit 64 is absorbed by the drum through countershaft 59, the hydraulictransmission |20, shaft 24 and chains 5| and 55. This requires thatclutches 28 and 58 be disengaged. Clutches 43, ||9 and |26 are engaged.No air `is supplied either to the pipe |09 or to the pipe 96a oftransmission unit 64. Under these circumstances, power supplied to theinput shaft 6.0 of the transmission is transmitted through thetransmission unit 63 to the planet cage Ill of the transmission unit 64.Since at this time the ring gear housing |08 of the transmission unitt4` is connected to the hoisting drum through gears ||6 and shaft 59,chain |22, transmission |20, shaft 24 and chains 5I and 55, it will berotated backwardly by the drum at low speed as the cable unwinds duringthe drilling operation and the sun gear i01 will be rotated forwardly toeiect forward rotation of the shaft 34 and, consequently, of the tabledriven at either of two speed ratios, depending upon the setting oftransmission unit 53, the lower speed ratio being a 1 to 1 driveconnection between the sleeve 25 and the sprocket I0 and the higherbeing a 1 to 2 overdrive between the sleeve 25 and the sprocket' I0. Thering gear housing |08 will be subject to a table reaction force tendingto rotate it forwardly, and that force will at all times be proportionalto the torque delivered to the rotary table I. That reaction force, inturn, is transmitted through gears 6 and IIT, shaft 59 and chain |22 tothe hydraulic transmission |20. transmission unit |20 will resistunwinding of the drum and thus assist in supporting the drill stem, andthe value of this resistance will at .all times vary in exact proportionto the table torque.

The hydraulic connections between the pump |28 and the motor |27 of thetransmission |20 are so 1 arranged that the sprocket |2| of the pumptends `to rotate in the opposite direction to the torque applied tosprocket |23 of the motor in order that the torque supplied by thetransmission |20.

to the shaft 59 will act in a direction to sustain the table torquereaction on the ring gear housing |08.

, Actually, the total torque supplied to the hoisting drum from bothsources will be insuiicient normally to support the entire weight ofthedrill stem, leaving a residual portion of the weight effective tocreate the desired drill bit pressure. As a result, as the drillingoperation progresses,

the drill stem will automatically lower, causing an unwinding or reverserotation of the drum 2.

.is entirely independent of drum speed and the percentage rate of changeof drill stem support- Aing torque is substantially less than thecorresponding percentage rate of change inthe table The table may be Asa result, tthe 14 torque. This eliminates objectionable hunting, whichwould otherwise result.

An important feature of the present apparatus resides in the provisionof a relatively small, com'- pact, infinitely variable transmission |20,by means of which the rate of change of the drill stem supporting torquefor a given change in table torque may be adjusted through an infiniterange to any desired value by manipulations of the hand wheel |35. Thus,the total drill stem supporting torque and its degree of responsivenessto table torque may both be adjusted to any desired degree byadjustments of the engine throttle and the position of the hand wheel|35. While an infinitely variable change-speed trans'- mission ispreferred for this purpose, it will be apparent to those skilled in theart that any of the many well recognized forms of change-speedtransmissions may be employed to advantage in this connection.

Another important feature of the invention resides in the use of arelatively low torque planetary transmission for changing the speedratios between the engines and the hoisting drum or rotary table incombination with an auxiliary drive for the lowest speed ratiosindependent of the transmission. Still another feature resides in theprovision of an auxiliary reversing drive connection in the form of acountershaft associated with the planetary transmission, which shaft maybe employed either to obtain the necessary reverse drives or to transmitto the hoisting drum the table torque reaction during automaticdrilling.

While the complete apparatus involves a number of gear drivingconnections and a number of chain driving connections, it will beapparent to those skilled in the art that gear driving connections maybe substituted for any of the chain drives, and that chain drives may besubstituted for gear drives except in the planetary transmission,without departing from the principles of the invention. Likewise, otherforms of planetary or differential gear sets may be substituted for thetvpe illustrated and described.

It is highlv desirable. in change-gear transmissions employed inconnection with heavy duty hoisting enuinment. that shifts in the gearratio, particularly from lower to higher ratios. be accomplished duringthe hoisting operation with a minimum danger of dropping the hoistedload intermediate engagement of the two sets of `gears. For this reason,transmissions employing disengageable gears or jaw clutches areundesirable es compared with any form of constant lmesh planetary geartransmission employing friction clutches for effecting changes in thegear ratio. For that reason. this form of planetarygear transmission ispreferred. Howevery even with such planetary transmissions it ispossible, as the result of defective operation of the shiftingmechanism, to disengage one gear ratio and either fail or delay ineffecting the next gear ratio. The preferred form of transmission'mechanism disclosed in the application incor- Levent. the cone clutcheswhich maintain the .transmissionsin :their low gear-ratios 'will remainengaged until after theone-way clutch blocks engage the ring gearhousings and tend to bring the :ring .gear housings to a'stop. The forcethus exerted will be transmitted through the helical splines 99 and maand will be effective to complete the disengaging operation of the coneclutches. Thus, no disengagement can occur until .the one-way brakeblocks 89 are engaged.

While ythe transmission does not operate in a similar manner lon shiftslfrom Va high to a low gear ratio, this is relatively unimportant in a:hoisting transmission for the reason vthat any given hoisting operationis normally started in low gear and the only shifts in `theAtransmission speed'ratios `which are required during thehoist- `ing.operation are shifts to the higher gear ratios `as the load speeds up.It should be noted, however, that in order to insure `a `shift of thetransmission from a high gear ratio to a low gear ratio under load,which might occur under Yunusual circumstances, it is necessary that'the springs 97 be of sufficient strength 'to exert a total forcesufficient to overcome the maximum torque reaction on the ring gear whenthe transmission is in its 1 'to 2 `overdrive ratio and the air.supplied to the pipes 96 is cut off, in order that the Ysprings mayeffect disengagement of the one- `way brake blocks 89. In addition, theengagement of cone clutches at this time must be delayed until therone-way 'brake blocks 89 can be disengaged. This delay may be effectedin any `desired manner, asby restricting the air supply line whichcontrols the engagement of vthe cone clutches.

Whileonly one form o'f the invention is shown and described herein, itwill be apparent that variations 'in the arrangement of the variousparts and the design `and construction thereof Amay be indulged Vinwithout departing from the spirit of the invention or the scope of theappended claims.

' What is claimed is:

1. Mechanism for operating a rotary well drilling machine andautomatically controlling the drill bit'pressure, including a hoistingdrum operating shaft, a table operating shaft, a pair of independentlyoperable power input shafts, a differential gear set having threeinterconnected `rotary members, a drive connection between one 'of saidmembers and one of said input shafts, a drive Yconnection between thesecond of said members and the table shaft, and a positive drive`connection between the third of said members 'and said vdrum shaft,said last mentioned drive connection including archange-.speed ratiopositive torque transmission, and a drive connection between the otherinput shaft and the drum `shaft independent of said change speedtransmission.

2. Mechanism for operating a rotary well drilling machine andautomatically controlling the .drill bit pressure, including a hoistingdrum operating shaft, a table operating shaft, a pair of independentlyoperable power input shafts, a differential gear set having threeinterconnected rotary members, a drive `connection between one Lof saidmembers and one of said input shafts, a drive connection between thesecond of said `members and the table shaft, and a positive driveconnection between the third of said members .and `said drum shaft, saidlast mentioned drive v.connection including an infinitely variable speed:ratio positive torque transmission, vand a drive :connection .betweenthe .other yinputshaft .and

the drum shaft independent of sai'dchange speed transmission.

`3. Mechanism for operating a rotary well drilling machine andautomatically controlling the drill bit pressure, including a hoistingdrum op erating shaft, a table operating shaft, `a pair `ofindependently operable power input shafts, a differential gear sethaving three interconnected rotary members, a drive connection betweenone of said members and one of said input shafts, a drive connectionbetween the second of 'said members and the table shaft, and a positivedrive connection between the third of said members and :said drum shaft,said last mentioned drive connection including an infinitely variablespeed ratio Apositive displacement hydraulic transmission, and a driveconnection between the other input shaft and the drum shaft independentof said change speed transmission.

4. Mechanism for operating a'rotary'well drilling machine andautomatically controlling vthe drill bit pressure, including a hoistingdrum operating shaft, a table operating shaft, a pair of independentlyoperable power input shafts, `a differential gear set having threeinterconnected rotary members, a drive connection between one of saidmembers and one of said input shafts, a drive connection between thesecond of said members and the table shaft, and a positive driveconnection between the third of said members and said drum shaft, saidlast mentioned drive connection including a change-speed ratio positivetorque transmission, the portion of said'last mentioned driveconnectionbetween said third member and the said last mentionedtransmission including a torque reducing drive and the portion betweensaid last mentioned transmission and the drum shaft including Ya torqueincreasing drive in order to reduce the torque load imposed on said lastmentioned transmission, and a drive connection between the otherinput-shaft and the drum shaft independent of said change speedtransmission.

5. Mechanism for operating a rotary well drilling machine andautomatically controlling the drill bit pressure, including `a hoistingdrum operating shaft, a table operating shaft, a pair `of independentlyoperable power input shafts, a differential gear set having threeinterconnected rotary members, a drive connection between one of Vsaidmembers and one of said input shafts, a drive connection between thesecond of said members and the table shaft, and a positive driveconnection between the third of said members and said drum shaft, saidlast mentioned drive connection including an infinitely variable speedratio positive torque transmission, the portion of said last mentioneddrive connecten between said third member and the said last mentionedtransmission including a torque reducing drive and the portion betweensaid last mentioned transmission and the drum shaft including a torqueincreasing drive in order to reduce the torque load imposed on said lastmentioned transmission, and a drive connection between the other inputshaft and the drum shaft independent of said change speed transmission.

6. Mechanism for operating a rotary vwell drilling machine andautomatically controlling the drill bit pressure, including a hoistingdrum operating shaft, a table operating shaft, a pair of independentlyoperable power input shafts, a differential gear vset having threeinterconnected rotary members, a drive connection'between one :of.said-members and one of said input shafts.

stresses a 'drive connection between-` the" second of said members'andthetable shaft, anda positive drive connection between the third of saidmembers and said drum shaft;` said lastmentioned drive connectionincluding aninnitelyvariable speed ratio positive displacement hydraulictransmission, the portionof said last mentionedv drive connectionbetweensaid thirdmember and the said last mentioned transmissionincluding a torque reducing drive and the portion between said lastmentioned transmission and the drum shaft including a torque increasingdrive in order to reduce the torque load imposed on said last mentionedtransmission, and a drive connection between the other input shaftandthe drum shaft independent of said change speed transmission.

7. A transmissionfor a rotary well drillingr machine, comprising` a`supporting frame, a main shaftjournaled on the frame, a table drivingelement journaled on the frame, a drum driving element journaled on theframe, a power input shaft, driving means including a disengageableclutch for connecting said power input shaft to said drum drivingelement, a planetary gear set comprising a pair of rotary gear membersconnected by planet gears which are journaled on a rotary planet cagemember, one of saidmembers being `connected to said main shaft, drivingmeans including a disengageable clutch for con nectingsaid powerinputshaft to another of said members, a driving connection including adisengageable clutch between the third member of the planetary gear `setand said drum driving element independent of said main shaft, saiddriving means for connecting `the power input shaft to said drum elementbeing operative independently of said third member of the planetary gearset,4 means selectively operable to prevent relative rotation betweensaid members, a brake operable to hold one of said members stationary,and driving connections including independently operable clutches forconnecting the main shaft to said drum driving element and said tabledriving element, respectively.

8. A transmission for a rotary well drilling machine, comprising asupporting frame, a main shaft journaled on the frame, a table drivingelement journaled on the frame, a drum driving element journaled on theframe, a power input shaft, driving means including a disengageableclutch for connecting said power input shaft to said drum drivingelement, a sun gear on said main shaft, a ring gear member journaled onsaid frame, a planet cage member journaled on said frame, planet gearsjournaled on said cage and operatively connecting said sun and ringgears, driving means including a disengageable clutch for connectingsaid power input shaft to said planet cage, a reversing drivingconnection including a disengageable clutch between the ring gear memberand said drum driving element and independent of the main shaft, abrake' operable to hold said ring gear member stationary, a clutchoperable to prevent relative rotation between said members, and drivingconnections including independently operable clutches for connecting themain shaft to said drum driving element and said table driving element,respectively.

9. A transmission for a rotary well drilling machine, comprising asupporting frame, a main shaft journaled on the frame, a table drivingelement journaled on the frame, a drum driving element journaled on theframe, a power input shaft, driving means including a disengageableclutch' for connecting-isaidvower input" shaft; to said-drum drivingelement, a planetary gear set comprising aipair of rotary gear members`con-- nected by' planet gears which are journaledtonl a rotary planet;cage member, one of saidmembers being connected to said main shaft,driving meansincluding a disengageable clutch forconnectingsaidpowerinput shafttoanother of said members,` a-drivingfconnection including" a dis`- engageable 'clutch and a change-speedratio transmissionbetween the third member of the planetary `g'ea'r setand said drum driving ele` ment independent of said main shaft, meansselectively operable toprevent relative rotation between said members, abrake operable to hold oneof saidfmembersstationary, and drivingconnections" including i independently operable c'lutchesifor connectingthe main shaft tosaid driim` drivingA element andlsaidY table drivingelem'e`nt,--res`pectively.` Y

10.A transmission for a`rotary well drilling machine, comprising asupporting frame,` amain shaftijornaledton `theframe, a table drivingelement journaled on` the frame, a drum" driving element journaled onthe frame, a powerinput sliaft, driving means including a disengageableclutch for connecting saidpower input shaft to said drumdriving element,a sungear on said main shaft, a ringgearmember journaled on said frame;a planet-cagefmemberjournaledfon said framefplanet gears journaledofisaid cage and operatively connecting" said'sun and ring gears,driving means including a disengageable, clutch for connectingsaidpowerinpu't shaftto said pianetcage, a driving connection betweenthe ring` gear meinber and said drum Ydriving element independent of themain shaft aridinclud` ing adisengageable clutch and a` change-speedratio transmission, a brake operable to hold said ring gear memberstationary, a clutch operable to prevent relative rotation between saidmembers, and driving connections including independently operableclutches for connecting the main shaft to said drum driving element andsaid table driving element, respectively.

11. A transmission for a rotary well drilling machine, comprising asupporting frame, a main shaft journaled on the frame, a table drivingelement journaled on the frame, a drum driving element journaled on theframe, a power input shaft, driving means including a disengageableclutch for connecting said power input shaft to Said drum drivingelement, a sun gear on said main shaft, a ring gear member journaled onsaid frame, a planet cage member journaled on said frame, planet gearsjournaled on said cage and operatively connecting said sun and ringgears, driving means including a disengageable clutch for connectingsaid power input shaft to said planet cage, a reversing drivingconnection including a disengageable clutch between the ring i gearmember and said drum driving element and Jar gear, a plurality of planetgear clusters each comprising a pair of gears of different sizes fixedtogether with the smaller gear of each cluster in mesh with said sungear, a planet cage for supporting and journaling said planet clusters,an internal gear member surrounding said planet cage and in mesh withthe larger gears of said clusters, a clutch element mounted on saidplanet cage outwardly of the planet clusters, a clutch surface on saidinternal gear member adapted for engagement With said element, saidclutch element having a helical spline connection with said cage, thehelix angle being such that the load imposed on said clutch element whenengaged with said surface tends to cause disengagement of the clutchelement from said surface when torque is applied to the` planet cage andresistance is oiered to rotation of the internal gear, means forengaging and disengaging said clutch element and surface, and a brakeadapted on operation to hold said internal gear member against rotation.

13. A two-speed transmission comprising a sun gear, a plurality ofplanet gear clusters each comprising a pair of gears of different sizesxed together with the smaller gear of each cluster in mesh with said sungear, a planet cage for supporting and journaling said planet clusters,said cage being an integral unit comprising a pair of parallel spacedannular side plates connected by a plurality of circumferentially spacedaxially extending webs, said plates being provided With alignedopenings, removable pins having their ends fixed Within said openings insaid side plates and constituting journals for said gear clusters, saidcage including a cylindrical Wall portion extending axially from one ofthe side plates over the smaller gears of said clusters,

an internalgear member surrounding said planet cage and in mesh with thelarger gears oi said clusters, a clutch element mounted on saidcylindrical wall portion of said planet cage outwardly of the planetclusters, a clutch surface on the interior of said internal gear memberadapted for engagement with said element, said clutch element having ahelical spline connection with said cylindrical wall portion of thecage, the helix angle being such that the load imposed on said clutchelement when engaged with said surface tends to cause disengagement ofthe clutch element from said surface when said planet cage is thedriving member and resistance is offered to rotation of the internalgear, means for engaging and disengaging said clutch element andsurface, and a brake adapted on operation to hold said ring gear housingagainst rotation.

CHARLES M. OLEARY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS France Sept. 15, 1921

